Socket 3 was a series of CPU Sockets for various x86microprocessors. It was sometimes found alongside a secondary socket designed for a math coprocessor chip, in this case the 487. Socket 3 resulted from Intel's creation of lower voltage microprocessors. An upgrade to Socket 2, it rearranged the pin layout and omitted one pin so that 3.3 V processors could not be plugged into older 5 V only sockets.

1.
Zero insertion force
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Zero insertion force is a type of IC socket or electrical connector that requires very little force for insertion. The lever is moved back, allowing the contacts to close. ZIF sockets are more expensive than standard IC sockets and also tend to take up a larger board area due to the space taken up by the lever mechanism. Therefore they are used when there is a good reason to do so. A normal integrated circuit socket requires the IC to be pushed into sprung contacts which then grip by friction, for an IC with hundreds of pins, the total insertion force can be very large, leading to a danger of damage to the device or the circuit board. Low insertion force sockets reduce the issues of insertion and extraction, large ZIF sockets are only commonly found mounted on PC motherboards, being used from about the mid 1990s forward. These CPU sockets are designed to support a range of CPUs, allowing computer retailers and consumers to assemble motherboard/CPU combinations based on individual budget. The rest of the industry has largely abandoned sockets and instead moved to the use of surface mount components soldered directly to the board. Smaller ZIF sockets are used in chip-testing and programming equipment, e. g. programming and testing on EEPROMs, Microcontrollers. Standard DIP packages come in a number of widths, with 0.3 in and 0.6 in being the most common, to allow design of programmers and similar devices that support a range of devices universal test sockets are produced. These have wide slots into which the pins drop allowing devices of differing widths to be inserted, ZIF sockets can be used for ball grid array chips, particularly during development. These sockets tend to be unreliable, failing to grab all the solder balls, another type of BGA socket, also free of insertion force but not a ZIF socket in the traditional sense, does a better job by using spring pins to push up underneath the balls. ZIF wire-to-board connectors are used for attaching wires to printed circuit boards inside electronic equipment, an example would be the cable between the LCD screen and motherboard in laptops. The wires, often formed into a cable, are pre-stripped. The two sliding parts of the connector are then pushed together, causing it to grip the wires, the most important advantage of this system is that it does not require a mating half to be fitted to the wire ends, therefore saving space and cost inside miniaturised equipment. ZIF tape connections are used for connecting Parallel ATA and Serial ATA disk drives, PATA hard drives with ZIF-style connectors were used primarily in the design of ultra-portable notebooks. They have since been phased out, as SATA has a relatively small-form-factor connector by default, mini-SATA can be used where even smaller form factors are required. Internally, nearly all hard drives use ZIF tape to connect their circuit board to their platter motor

2.
Intel
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Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California that was founded by Gordon Moore and Robert Noyce. It is the worlds largest and highest valued semiconductor chip makers based on revenue, and is the inventor of the x86 series of microprocessors, Intel supplies processors for computer system manufacturers such as Apple, Lenovo, HP, and Dell. Intel Corporation was founded on July 18,1968, by semiconductor pioneers Robert Noyce and Gordon Moore, the companys name was conceived as portmanteau of the words integrated and electronics. The fact that intel is the term for intelligence information made the name appropriate. Intel was a developer of SRAM and DRAM memory chips. Although Intel created the worlds first commercial microprocessor chip in 1971, during the 1990s, Intel invested heavily in new microprocessor designs fostering the rapid growth of the computer industry. The Open Source Technology Center at Intel hosts PowerTOP and LatencyTOP, and supports other projects such as Wayland, Intel Array Building Blocks, and Threading Building Blocks. Client Computing Group – 55% of 2016 revenues – produces hardware components used in desktop, data Center Group – 29% of 2016 revenues – produces hardware components used in server, network, and storage platforms. Internet of Things Group – 5% of 2016 revenues – offers platforms designed for retail, transportation, industrial, buildings, non-Volatile Memory Solutions Group – 4% of 2016 revenues – manufactures NAND flash memory products primarily used in solid-state drives. Intel Security Group – 4% of 2016 revenues – produces software, particularly security, programmable Solutions Group – 3% of 2016 revenues – manufactures programmable semiconductors. In 2016, Dell accounted for 15% of Intels total revenues, Lenovo accounted for 13% of total revenues, in the 1980s, Intel was among the top ten sellers of semiconductors in the world. In 1991, Intel became the biggest chip maker by revenue and has held the position ever since, other top semiconductor companies include TSMC, Advanced Micro Devices, Samsung, Texas Instruments, Toshiba and STMicroelectronics. Competitors in PC chip sets include Advanced Micro Devices, VIA Technologies, Silicon Integrated Systems, however, the cross-licensing agreement is canceled in the event of an AMD bankruptcy or takeover. Some smaller competitors such as VIA Technologies produce low-power x86 processors for small factor computers, however, the advent of such mobile computing devices, in particular, smartphones, has in recent years led to a decline in PC sales. Since over 95% of the worlds smartphones currently use processors designed by ARM Holdings, ARM is also planning to make inroads into the PC and server market. Intel has been involved in disputes regarding violation of antitrust laws. Intel was founded in Mountain View, California in 1968 by Gordon E. Moore, a chemist, and Robert Noyce, arthur Rock helped them find investors, while Max Palevsky was on the board from an early stage. Moore and Noyce had left Fairchild Semiconductor to found Intel, Rock was not an employee, but he was an investor and was chairman of the board

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Intel 80486SX
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Intels i486SX was a modified Intel 486DX microprocessor with its floating-point unit disabled. It was intended as a lower-cost CPU for use in low-end systems, computer manufacturers that used these processors include Packard Bell, Compaq, ZEOS and IBM. In the early 1990s, common applications did not need or benefit from an FPU, among the rare exceptions were CAD applications, which could often simulate floating point operations in software, but benefited from a hardware floating point unit immensely. Intel wanted to provide a lower cost i486 CPU for system integrators and this was accomplished through a debug feature called Disable Floating Point, by grounding a certain bond wire in the CPU package. The i486SX was introduced in mid-1991,18 months after the i486DX, later versions of the i486SX had the FPU entirely removed for cost cutting reasons. Some systems allowed the user to upgrade the i486SX to a CPU with the FPU enabled, the upgrade was shipped as the i487, which was a full blown i486DX chip with an extra pin. The extra pin prevents the chip from being installed incorrectly, the NC# pin, one of the standard 168 pins, was used to shut off the i486SX. This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the terms of the GFDL. Intel 80486SX images and descriptions at cpu-collection. de Intel Datasheets Embedded i486SX Embedded Ultra-Low Power i486SX

4.
Intel 80486
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The Intel 80486, also known as the i486 or 486, is a higher performance follow-up to the Intel 80386 microprocessor. It represents a generation of binary compatible CPUs since the original 8086 of 1978. A50 MHz 80486 executes around 40 million instructions per second on average and is able to reach 50 MIPS peak performance, the i486 does not have the usual 80-prefix because of a court ruling that prohibits trademarking numbers. Later, with the introduction of the Pentium brand, Intel began branding its chips with words rather than numbers, the 80486 was announced at Spring Comdex in April 1989. At the announcement, Intel stated that samples would be available in the quarter of 1989. The first 80486-based PCs were announced in late 1989, but some advised that people wait until 1990 to purchase a 80486 PC because there were reports of bugs. From a performance point of view, the architecture of the i486 is a vast improvement over the 80386 and it has an on-chip unified instruction and data cache, an on-chip floating-point unit and an enhanced bus interface unit. Due to the tight pipelining, sequences of simple instructions could sustain a single clock cycle throughput and these improvements yielded a rough doubling in integer ALU performance over the 386 at the same clock rate. A 16-MHz 80486 therefore had a similar to a 33-MHz 386. An 8 kB on-chip SRAM cache stores the most recently used instructions, the 386 had no such internal cache but supported a slower off-chip cache. Tightly coupled pipelining completes a simple instruction like ALU reg, reg or ALU reg, the 386 needed two clock cycles to do this. New instructions, XADD, BSWAP, CMPXCHG, INVD, WBINVD, virtual addresses were then normally mapped onto physical addresses by the paging system except when it was disabled. Just as with the 80386, circumventing memory segmentation could substantially improve performance in some operating systems, on a typical PC motherboard, either four matched 30-pin SIMMs or one 72-pin SIMM per bank were required to fit the 80486s 32-bit data bus. The address bus used 30-bits complemented by four byte-select pins to allow for any 8/16/32-bit selection and this meant that the limit of directly addressable physical memory was 4 gigabytes as well. There are several suffixes and variants, marked as upgrade processors, some models had different pinouts or voltage handling abilities from standard chips of the same speed stepping. Fitted to a coprocessor or OverDrive socket on the motherboard, worked the same as the i487SX, the specified maximum internal clock frequency ranged from 16 to 100 MHz. The 16 MHz i486SX model was used by Dell Computers, one of the few 80486 models specified for a 50 MHz bus initially had overheating problems and was moved to the 0.8 micrometre fabrication process. Certain steppings of the DX4 also officially supported 50 MHz bus operation but was a seldom used feature

5.
Am486
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The Am486 is a 80486-class family of computer processors that was produced by AMD in the 1990s. Intel beat AMD to market by nearly four years, but AMD priced its 40 MHz 486 at or below Intels price for a 33 MHz chip, offering about 20% better performance for the same price. While competing 486 chips, such as those from Cyrix, benchmarked lower than the equivalent Intel chip, AMDs higher clocked 486 chips provided superior performance to many of the early Pentium chips, especially the 60 and 66 MHz launch products. While equivalent Intel 80486DX4 chips were priced high and required a minor socket modification, Intels DX4 chips initially had twice the cache of the AMD chips, giving them a slight performance edge, but AMDs DX4-100 usually cost less than Intels DX2-66. The enhanced Am486 series supported new features like extended power-saving modes, the 133 MHz AMD Am5x86 was a higher clocked enhanced Am486. WT = Write-Through cache strategy, WB = Write-Back cache strategy AMD, part 2 cpu-collection. de AMD Am486 processor images and descriptions

6.
Am5x86
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The Am5x86 processor is an x86-compatible CPU introduced in 1995 by AMD for use in 486-class computer systems. It was one of the fastest, and most universally compatible upgrade paths for users of 486 systems, like all Enhanced Am486, the Am5x86 featured write-back L1 cache, and unlike all but a few, a generous 16 kilobytes rather than the more common 8 KB. A rare 150 MHz-rated OEM part was released by AMD. Since having a clock multiplier of four was not part of the original Socket 3 design, AMD made the 5x86 accept a 2x setting from the motherboard, when using an Am5x86, the motherboard must be set to the 2x setting.45 volts. The combination of speed and the relatively large 16 KB write-back L1 cache allowed the 5x86 to equal or slightly exceed an Intel Pentium 75 MHz processor in integer arithmetic in benchmarks. Also, because it was based on a pure 486 design, it was compatible with systems, something its slightly faster rival. The CPU was commonly overclocked to 160 MHz, thereby giving performance similar to that of a Pentium 90 MHz system, there are four main versions of the socketed version of this CPU, manufactured in different locations. There is the common ADW variety, as well as the later ADY, ADZ, the later models were the preferred versions of the chip, because they were rated for higher temperatures and thus more forgiving of overclocking. The Am5x86 is also notable for the use of the controversial PR rating. Because the 5x86 was the equal of a Pentium 75 MHz processor in benchmarks, sales of the Am5x86 were an important source of revenue for AMD at a time when lengthy delays in bringing the AMD K5 to production were threatening the companys profitability. AMD manufactured the Am5x86 processor for ordinary PC systems until 1999 and it was popular for entry-level desktop systems, appeared in many different notebook models, and also sold separately as an upgrade processor for older 486 systems. Several companies made upgrade kits which packaged an AMD 5x86 with a regulator and socket converter. Several companies also provided upgrades for older 486 notebooks by replacing soldered 486 CPUs, the chips were even used on later Acorn RiscPC PC card second processors. The RiscPCs OpenBus only supported a 32-bit memory interface, which meant that the Pentium could not be easily interfaced to it, intels expensive Pentium Overdrive for 486 systems was a troublesome CPU, with many compatibility issues, and so was not used. The 5x86 therefore provided the acme of RiscPC Windows performance, the chip remained in production for a long time, as it was a popular choice for use in embedded controllers. One derivative of the 5x86 family is the used in the Élan SC520 family of microcontrollers marketed by AMD. This powered the original Cisco PIX, data from AMD, The Am5x86 Microprocessor CPU Upgrade, Give your 486 PC a kick with the AMD 5x86 -133. Gallery including Am586 images at Cpushack. com AMDs Élan µController family AMD 5x86 processor images and descriptions at cpu-collection. de

7.
X86
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X86 is a family of backward-compatible instruction set architectures based on the Intel 8086 CPU and its Intel 8088 variant. The term x86 came into being because the names of several successors to Intels 8086 processor end in 86, many additions and extensions have been added to the x86 instruction set over the years, almost consistently with full backward compatibility. The architecture has been implemented in processors from Intel, Cyrix, AMD, VIA and many companies, there are also open implementations. In the 1980s and early 1990s, when the 8088 and 80286 were still in common use, today, however, x86 usually implies a binary compatibility also with the 32-bit instruction set of the 80386. An 8086 system, including such as 8087 and 8089. There were also terms iRMX, iSBC, and iSBX – all together under the heading Microsystem 80, however, this naming scheme was quite temporary, lasting for a few years during the early 1980s. Today, x86 is ubiquitous in both stationary and portable computers, and is also used in midrange computers, workstations, servers. A large amount of software, including operating systems such as DOS, Windows, Linux, BSD, Solaris and macOS, functions with x86-based hardware. There have been attempts, including by Intel itself, to end the market dominance of the inelegant x86 architecture designed directly from the first simple 8-bit microprocessors. Examples of this are the iAPX432, the Intel 960, Intel 860, however, the continuous refinement of x86 microarchitectures, circuitry and semiconductor manufacturing would make it hard to replace x86 in many segments. The table below lists processor models and model series implementing variations of the x86 instruction set, each line item is characterized by significantly improved or commercially successful processor microarchitecture designs. Such x86 implementations are seldom simple copies but often employ different internal microarchitectures as well as different solutions at the electronic, quite naturally, early compatible microprocessors were 16-bit, while 32-bit designs were developed much later. For the personal computer market, real quantities started to appear around 1990 with i386 and i486 compatible processors, other companies, which designed or manufactured x86 or x87 processors, include ITT Corporation, National Semiconductor, ULSI System Technology, and Weitek. Some early versions of these microprocessors had heat dissipation problems, AMD later managed to establish itself as a serious contender with the K6 set of processors, which gave way to the very successful Athlon and Opteron. There were also other contenders, such as Centaur Technology, Rise Technology, VIA Technologies energy efficient C3 and C7 processors, which were designed by the Centaur company, have been sold for many years. Centaurs newest design, the VIA Nano, is their first processor with superscalar and it was, perhaps interestingly, introduced at about the same time as Intels first in-order processor since the P5 Pentium, the Intel Atom. The instruction set architecture has twice been extended to a word size. In 1999-2003, AMD extended this 32-bit architecture to 64 bits and referred to it as x86-64 in early documents, Intel soon adopted AMDs architectural extensions under the name IA-32e, later using the name EM64T and finally using Intel 64

8.
Microprocessor
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A microprocessor is a computer processor which incorporates the functions of a computers central processing unit on a single integrated circuit, or at most a few integrated circuits. Microprocessors contain both combinational logic and sequential digital logic, Microprocessors operate on numbers and symbols represented in the binary numeral system. The integration of a whole CPU onto a chip or on a few chips greatly reduced the cost of processing power. Integrated circuit processors are produced in numbers by highly automated processes resulting in a low per unit cost. Single-chip processors increase reliability as there are many electrical connections to fail. As microprocessor designs get better, the cost of manufacturing a chip generally stays the same, before microprocessors, small computers had been built using racks of circuit boards with many medium- and small-scale integrated circuits. Microprocessors combined this into one or a few large-scale ICs, the internal arrangement of a microprocessor varies depending on the age of the design and the intended purposes of the microprocessor. Advancing technology makes more complex and powerful chips feasible to manufacture, a minimal hypothetical microprocessor might only include an arithmetic logic unit and a control logic section. The ALU performs operations such as addition, subtraction, and operations such as AND or OR, each operation of the ALU sets one or more flags in a status register, which indicate the results of the last operation. The control logic retrieves instruction codes from memory and initiates the sequence of operations required for the ALU to carry out the instruction, a single operation code might affect many individual data paths, registers, and other elements of the processor. As integrated circuit technology advanced, it was feasible to manufacture more and more complex processors on a single chip, the size of data objects became larger, allowing more transistors on a chip allowed word sizes to increase from 4- and 8-bit words up to todays 64-bit words. Additional features were added to the architecture, more on-chip registers sped up programs. Floating-point arithmetic, for example, was not available on 8-bit microprocessors. Integration of the point unit first as a separate integrated circuit and then as part of the same microprocessor chip. Occasionally, physical limitations of integrated circuits made such practices as a bit slice approach necessary, instead of processing all of a long word on one integrated circuit, multiple circuits in parallel processed subsets of each data word. With the ability to put large numbers of transistors on one chip and this CPU cache has the advantage of faster access than off-chip memory, and increases the processing speed of the system for many applications. Processor clock frequency has increased more rapidly than external memory speed, except in the recent past, a microprocessor is a general purpose system. Several specialized processing devices have followed from the technology, A digital signal processor is specialized for signal processing, graphics processing units are processors designed primarily for realtime rendering of 3D images

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X87
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X87 is a floating point-related subset of the x86 architecture instruction set. It originated as an extension of the 8086 instruction set in the form of floating point coprocessors that worked in tandem with corresponding x86 CPUs. These microchips had names ending in 87 and this was also known as the NPX. Most x86 processors since the Intel 80486 have had these x87 instructions implemented in the main CPU, before x87 instructions were standard in PCs, compilers or programmers had to use rather slow library calls to perform floating-point operations, a method that is still common in embedded systems. There are instructions to push, calculate, and pop values on top of this stack and this can also be reversed on an instruction-by-instruction basis with ST as the unmodified operand and ST as the destination. Furthermore, the contents in ST can be exchanged with another stack register using an instruction called FXCH ST and these properties make the x87 stack usable as seven freely addressable registers plus a dedicated accumulator. Such a stack-based interface potentially can minimize the need to save scratch variables in function compared with a register-based interface. The x87 provides single precision, double precision and 80-bit double-extended precision binary floating-point arithmetic as per the IEEE 754-1985 standard, by default, the x87 processors all use 80-bit double-extended precision internally. A given sequence of operations may thus behave slightly differently compared to a strict single-precision or double-precision IEEE754 FPU. Clock cycle counts for examples of typical x87 FPU instructions, the A~B notation covers timing variations dependent on transient pipeline status as well as the arithmetic precision chosen, it also includes variations due to numerical cases. The L→H notation depicts values corresponding to the lowest and the highest maximum clock frequencies that were available, * An effective zero clock delay is often possible, via superscalar execution. § The 5 MHz 8087 was the original x87 processor, compared to typical software-implemented floating point routines on an 8086, the factors would be even larger, perhaps by another factor of 10. The 8087 was the first math coprocessor for 16-bit processors designed by Intel and it was built to be paired with the Intel 8088 or 8086 microprocessors. However, the Intel 8231 floating-point processor was an earlier design and it was a licensed version of AMDs Am9511 of 1977. The family included the 32-bit Am9511 and Am9511A and the later 64-bit Am9512, the 80187 is the math coprocessor for the Intel 80186 CPU. It is incapable of operating with the 80188, as the 80188 has an 8 bit data bus, the 80187 did not appear at the same time as the 80186 and 80188, but was in fact launched after the 80287 and the 80387. The 80287 is the math coprocessor for the Intel 80286 series of microprocessors, Intels models included variants with specified upper frequency limits ranging from 6 up to 12 MHz. Later followed the i80287XL with 387 microarchitecture and the i80287XLT, a version intended for laptops

10.
Pin grid array
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A pin grid array, often abbreviated PGA, is a type of integrated circuit packaging. In a PGA, the package is square or rectangular, the pins are commonly spaced 2.54 mm apart, and may or may not cover the entire underside of the package. PGAs are often mounted on printed circuit boards using the through hole method or inserted into a socket, pGAs allow for more pins per integrated circuit than older packages such as dual in-line package. Plastic pin grid array packaging was used by Intel for late model Mendocino core Celeron processors based on Socket 370, some pre-Socket 8 processors also used a similar form factor, although they were not officially referred to as PPGA. A flip-chip pin grid array is a form of pin grid array in which the die faces downwards on the top of the substrate with the back of the die exposed and this allows the die to have a more direct contact with the heatsink or other cooling mechanism. The FC-PGA was introduced by Intel with the Coppermine core Pentium III and Celeron processors based on Socket 370, FC-PGA processors fit into zero insertion force Socket 370 and Socket 478-based motherboard sockets, similar packages have also been used by AMD. It is still used today for mobile Intel processors, the Staggered pin grid array is used by Intel processors based on Socket 5 and Socket 7. Socket 8 used a partial SPGA layout on half the processor and it consists of two square arrays of pins, offset in both directions by half the minimum distance between pins in one of the arrays. Put differently, within a square boundary the pins form a square lattice. There is generally a section in the center of the package without any pins, SPGA packages are usually used by devices that require a higher pin density than what a PGA can provide, such as microprocessors. A ceramic pin grid array is a type of packaging used by integrated circuits and this type of packaging uses a ceramic substrate with pins arranged in a pin grid array. Some CPUs that use CPGA packaging are the AMD Socket A Athlons, a CPGA was used by AMD for Athlon and Duron processors based on Socket A, as well as some AMD processors based on Socket AM2 and Socket AM2+. While similar form factors have been used by manufacturers, they are not officially referred to as CPGA. This type of packaging uses a ceramic substrate with pins arranged in an array, a Stud Grid Array is a short-pinned pin grid array chip scale package for use in Surface-mount technology. The Polymer Stud Grid Array or Plastic Stud Grid Array was developed jointly by the Interuniversity Microelectronics Centre and Laboratory for Production Technology and it is used in the G1, G2, and G3 sockets. What the Hell is… a flip-chip, XSERIES335 XEON DP-2. 4G512 MB

11.
Cyrix Cx5x86
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Released in August 1995, four months before the more famous Cyrix 6x86, the Cyrix 5x86 was one of the fastest CPUs ever produced for Socket 3 computer systems. With better performance in most applications than an Intel Pentium processor at 75 MHz, the chip featured near-complete support for i486 instructions, but very limited support for Pentium instructions. Some performance-enhancing features of the CPU were intentionally disabled due to potentially stability-threatening bugs which were not fixed before release time, Cyrixs 5x86 was a very short-lived chip, having a market life of only six months. It is likely Cyrix could have continued to successfully sell processors based on Socket3, the official Cyrix 5x86 website boasted about several features of the chip that were disabled by default in the final versions. The most controversial of these features was the feature, which was enabled in the benchmarks results on the company website when comparing the chip to Intels Pentium processor. While it was possible to enable the features using a special software utility, it usually resulted in an unstable system. There are also many rumours surrounding a 133 MHz, clock-quadrupled version of the Cyrix 5x86, the 133 MHz version is very rare, however, and producers of upgrade kits were given preferential access to it, notably Gainbery. Some of the 100 and 120 MHz parts also contain support for the 4X multiplier setting, however, the 5x86 is not known to overclock well, and 120 MHz is generally considered to the pushing the limitations of the process on which it was fabricated. An 80 MHz 5x86 also exists, but is unclear as to whether or not it was officially released. IBMs 5x86C was considered to be more conservatively rated than the Cyrix branded parts, for example, what Cyrix would rate as a 100 MHz part, IBM would mark as 75 MHz. IBM 5x86C was available as 75MHz and 100MHz parts, a few examples of 120MHz parts also exist, but they have early production dates indicating that they may have been produced prior to IBMs decision to scale back clock speeds. 5x86C also had a longer production run than the Cyrix branded parts. IBM continued to produce 5x86C at least until late 1998, whereas Cyrixs own part was discontinued in 1996, no parts known to exist implement the 4X multiplier or Stepping 1 Rev 3 cores. IDX4WB pinout,168 pins Socket 32.0 million transistors on 0.65 micrometre process 144mm² die 3

12.
Chip carrier
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In electronics, a chip carrier is one of several kinds of surface mount technology packages for integrated circuits. Connections are made on all four edges of a package, Compared to the internal cavity for mounting the integrated circuit. Chip carriers may have either J-shaped metal leads for connections by solder or by a socket, if the leads extend beyond the package, the preferred description is flat pack. Chip carriers are smaller than dual in-line packages and since they use all four edges of the package can have a pin count. Chip carriers may be made of ceramic or plastic, some forms of chip carrier package are standardized in dimensions and registered with trade industry associations such as JEDEC. Other forms are proprietary to one or two manufacturers, sometimes the term chip carrier is used to refer generically to any package for an integrated circuit. It is a reduced cost evolution of the ceramic chip carrier. A premolded PLCC was originally released in 1976, but did not see much market adoption, texas Instruments later released a postmolded variant that was soon adopted by most major semiconductor companies. The PLCC utilizes a J-lead with pin spacings of 0.05, the metal strip forming the lead is wrapped around and under the edge of the package, resembling the letter J in cross-section. Lead counts range from 20 to 84, PLCC packages can be square or rectangular. Body widths range from 0.35 to 1.15, the PLCC “J” Lead configuration requires less board space versus equivalent gull leaded components, which have flat leads that extend out perpendicularly to the narrow edge of the package. The PLCC is preferred over DIP style chip carriers when lead counts exceed 40 pins due to the PLCCs more efficient use of surface area. The heatspreader versions are identical in form factor to the standard non-heatspreader versions, both versions are JEDEC compliant in all respects. The heatspreader versions give the designer greater latitude in thermally enhanced board level. RoHs compliant, lead-free & green material sets are now qualified standards, a PLCC circuit may either be installed in a PLCC socket or surface-mounted. PLCC sockets may in turn be surface mounted, or use through-hole technology, using a PLCC socket may be necessary in situations where the device requires stand-alone programming, such as some flash memory devices. Some through-hole sockets are designed for prototyping with wire wrapping, a specialized tool called a PLCC extractor facilitates the removal of a PLCC from a socket. This package is used for a wide variety of device types